GMAT Critical Reasoning

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In the ruins of the city-state of Assur, in Ancient Assyria, archaeologists found dried goatskin dating back 3800 years. Analysis of the goatskins showed that they had an unusual pH level that was no lower than that of the calcium carbonate mixture produced by grinding cowrie shells, the most common seashells found on the shore of the Tigris river that runs through Assur. Some believe that this is evidence the Assyrians engaged in the practice of "liming" animal skins: soaking them in alkaline solutions made from crushed seashells in order to create parchment that could be traded with nearby civilizations.

Which of the following, if true, would, together with the information above, provide the best evidence for the claim that the dried goatskins are evidence that the Assyrians engaged in the practice of "liming" animal skins?

A The calcium carbonate from the cowrie shell is the most common chemical used in modern-day "liming" of parchment and leather.

B Apart from the Assur discovery, there is reliable evidence that some ancient civilizations, such as the Babylonians, practiced "liming."

C The goatskins were found in huts that contained equipment known to have been used by Assyrian tradesmen and chemists.

D Calcium carbonate mixtures of different concentrations can produce a wide range of pH levels in alkaline solutions.

E Archaeologists matched the goatskins to goat skeletons found on the outskirts of Assur on the banks of the Tigris River.